Compressible and expandable blade for a fluid pump

ABSTRACT

The invention relates to a compressible and expandable blade (2) for the rotor of a fluid pump (30) having at least two lamellae (3, 4, 5) which are disposed adjacently, are pivo table respectively relative to an axis of rotation (Ia) of the rotor and moveable relative to each other, and abut against each other in the expanded state of the blade such that they form together a continuous blade surface.

The present invention resides in the field of mechanics ormicromechanics and can be applied advantageously in particular inmedical technology.

The invention relates to a blade for a pump and the design thereof. Ofconcern thereby is a pump having a rotor, the rotor being compressibleand expandable in order to be able possibly to change the overalldimensions of the pump. In this way, the pump can be pushed through notreadily accessible openings or into narrow pipe systems, for whichpurpose it is firstly compressed and, after it has been moved to thelocation of use, is expanded again.

Such a pump can be used particularly advantageously in medicaltechnology in the field of heart pumps or other pumps for body fluidswhich are normally used with catheters.

In the technical medical field, different types of micropumps are known,which pumps can be introduced in the compressed state with a catheterthrough a naturally occurring body vessel into the body of a patient andcan be expanded in situ. In order to produce a corresponding radialcompressibility and expandability, various effects can be used in theconstruction and the structure of the pump housing and the pump rotor,such as e.g. the use of so-called memory alloys which change their shapeas a function of the ambient temperature or control the pump diameterspecifically by providing specific transmission mechanisms which allowit.

A solution is known from DE 10 2004 054 714 A1 in which both theimpeller of a micropump and the housing thereof is manipulated by amutual axial displacement of the pump drive shaft. As a result, thehousing is changed between a compressed and an expanded state.

A system is known from the patent document WO 00/2003103745 A2, in whichthe pump housing is likewise expanded mutually radially by an axialrelative movement of two components.

A rotor is known from the US patent specification U.S. Pat. No.7,393,181, the blade of which can be subdivided into a plurality ofpartial blades or rows of partial blades for improvedcompressibility/collapsibility. As a result of the subdivision, theindividual partial blades are smaller than a one-part blade and almostflat so that they can be rolled in easily. However, the ability to besubdivided is restricted by the intrinsic stability of the partialblades which requires to be ensured.

With the background of the state of the art, the object underlying thepresent invention is to produce a rotor which can be produced as simplyand economically as possible or a blade for such a rotor, highcompressibility being paramount with as little as possible of a forceexpenditure so that, in order to withdraw the pump from the vessel, thecompression of the pump rotor can be achieved without greater externalresistances. In addition, the corresponding pump is intended to bedesigned to be efficient and low-consumption.

The object is achieved according to the invention by the features ofpatent claim 1.

The invention provides a blade having a plurality of lamellae which aredisposed adjacently, are moveable relative to each other and pivotablerelative to an axis of rotation of the rotor, the lamellae abuttingagainst each other in the expanded state of the blade such that theyform together a continuous blade surface.

Due to their pivotability, lamellae of this type can be pivotedindividually very easily into a space-saving state and, in thepivoted-out, expanded state of the blade or of the rotor, form a closedblade surface which is designed such that it fulfils the requiredtechnical flow conditions with respect to shape and surface design.

Relative to a collapsible membrane, the blade consisting of individuallamellae has the advantage that its components can, both in thecompressed and in the expanded state, assume a defined shape andarrangement. The individual lamellae can respectively be mountedrotatably on the shaft of the rotor and in fact advantageously pivotablein a plane which includes the longitudinal axis of the rotor shaft or anaxis parallel to such a shaft, the mounting points being able to extendaround the rotor shaft in a spiral in order to produce a spiral blade inthe unfolded state. However, also other types of mounting areconceivable, in which the lamellae are mounted for example on one ormore webs or transverse spars which are connected, for their part, tothe rotor shaft.

The individual lamellae can be of equal length but can also be designedto be of different lengths according to which final shape the blade isintended to assume. The pivotability of the individual lamellae isrestricted so that these, in the opened state, can withstand the flowcounterpressure of a fluid to be conveyed. However, the lamellae canalso be mutually supported in that they abut against each other andpossibly engage in each other forming a lock. For example, the lamellaecan be designed in the manner of the elements of a bird feather, thequill of the feather corresponding comparatively to the rotor shaft.

The construction of the blade can be designed such that the bladeexpands during rotation in the operating direction due to the fluidcounterpressure and, when rotating in the opposite direction, iscompressed by the effect of the medium in which the blade moves. Thismakes the compression- and expansion movement particularly simplewithout greater forces requiring to be overcome. During application inthe medical field, such a pump can hence be removed again in a simplemanner and without the danger of damaging body vessels.

A particular embodiment of the invention provides that at least twolamellae, in particular each of the lamellae, have per se adimensionally stable, in particular rigid configuration.

The blade obtains its flexibility not from the flexibility of a membranebut from the movability of the individual lamellae relative to eachother. For this purpose, the lamellae must not exceed a specific width.Advantageously, the blade for example can consist of at least 10 or atleast 50 lamellae. Such a blade can have in total a very smallconstructional size in order to be inserted into a blood vessel,preferably less than 5 mm for example in the compressed state, adiameter of 2 mm.

A further advantageous embodiment of the invention can provide thatrespectively adjacent lamellae abut against each other to form a sealalong a longitudinal side which extends at least partially radiallyrelative to the rotor axis.

If it is even conceivable that the lamellae leave intermediate spacesbetween themselves, then the efficiency of the fluid pump in factincreases with the seal of the blade formed by the lamellae. It istherefore advantageous if the lamellae abut against each otherrespectively on their longitudinal side and as far as possible leave nointermediate space there.

It can be provided in addition that respectively lamellae which aremutually directly adjacent abut against each other in such a manner thatthey are not pivotable relative to each other about the rotor axis in atleast one direction. Hence, the individual lamellae can support eachother mutually and, during operation, entirely withstand thecounterpressure of the fluid to be pumped. In particular if the lamellaeare distributed in a spiral on the circumference of the rotor shaft,support is provided in the azimuthal direction.

The invention can be designed in addition such that respectivelyadjacent lamellae mutually overlap in the region of the longitudinalside. As a result of overlapping of the lamellae, particularly highimpermeability is produced and, in addition, the support function of thelamellae can be mutually exerted in the overlapping region.

Particularly high stability and impermeability between the lamellae isachieved in that respectively adjacent lamellae engage one in the otherin the region of the longitudinal side. Any type of form-fitting designof adjacent lamellae can thereby be provided, for example respectivelythe provision of a fold along the longitudinal sides of the lamellae,for example also in the form of a thin sealing lip.

In order to produce a form-fitting and sealed connection, it can also beprovided that at least one lamella, in particular all the lamellae, havea convex shape, in cross-section, on one of the longitudinal sidesthereof and a concave shape on the other longitudinal side. Thecorresponding convex or concave structure can, in cross-section, beround, elliptical or also configured as a groove or notch.

Advantageously, respectively adjacent lamellae can be connected to eachother by a flexible element, in particular a strip or a membrane. Theability of the blade to be opened out is then produced in the manner ofa fan, in the case of which broad, rigid support bars are connected toeach other by narrow membranes or strips.

In order to stabilise the individual lamellae these can respectivelyhave a stiffening structure in cross-section, which provides for examplea web extending in the longitudinal direction. However, it can also beprovided that, additionally or alternatively, the individual lamellaeare configured to be hollow with a round or square cross-section.

Advantageously, the invention can be configured by a blade in which atleast two lamellae are connected to each other by a chain-likeconnection. Such a chain-like connection consists of small hook-likeelements on the one side and blade-like elements on the respectivelyother side, which can be configured advantageously to be microscopicallysmall.

The invention can furthermore be designed advantageously in that theconnection is detachable by applying a load on the blade in the axialdirection of the rotor and/or by a relative movement of two adjacentlamellae along their respective longitudinal sides and in thelongitudinal direction of the lamellae.

The longitudinal direction of the lamellae is thereby dictated by thedirection in which the respective lamella extends away from the rotorshaft.

As a result of the described structure of a blade for the rotor of afluid pump, said blade can be designed to be particularly stable andcompressible in a defined manner, as a result of which in particulargood compressibility and a small final diameter of the rotor can beachieved in the compressed form.

A development provides that a compressible and expandable blade for therotor of a fluid pump, in particular a catheter pump, is provided, atleast two lamellae which are disposed adjacently being pivotablerespectively relative to an axis of rotation of the rotor and beingmoveable relative to each other and abutting against each other in theexpanded state in such a manner that they form together a continuousblade surface, the at least two adjacently-disposed lamellae belongingto different rotor segments, one rotor segment comprising at least onelamella and also a hub segment.

As a result, it becomes possible to construct a rotor “sequentially”,layering of individual rotor segments hereby being provided in the axialdirection. These rotor segments need not be (but might) welded etc. toeach other, it suffices that these are fixed non-rotatably relative toeach other. As a result of the fact that the rotor segments haverespectively at least one lamella and also one hub segment, theconnection to the rotor shaft can be provided by the hub segment or thehub segment can also represent an axial portion of the rotor shaftitself. By means of the combination of different hub segments, aninfluence can be made on the pitch of the helix. Hence, the economicalconstruction of a helix with an irregular pitch becomes possible, thepitch increasing advantageously in the conveying direction.

The rotor segments can be made of different materials, for example fromshape memory materials, in particular shape memory metals or shapememory plastic materials. In addition to “Nitinol”, polymers with thedesired properties are hereby possible.

A development hereby provides that the lamellae per se are respectivelyindividually coated and/or covered by a membrane, a connection of thecoating/membrane of two adjacent lamellae being at best frictionaland/or form-locking. As a result, the advantage of the “bird feather”principle is ensured, on the one hand, that the placing-around ofindividual lamellae frictionally (in particular when introducing into alock) is associated with low complexity, however, on the other hand (dueto the mutual support effect), a high fluid counterpressure can beproduced. As a result of the fact that the individual lamellae per se(or specific groups of lamellae combined) are respectively coatedindividually or are covered with a membrane, it is achieved that, in theboundary region of a plurality of lamellae/lamella groups, an evenbetter sealing effect is produced, on the one hand, by thecoating/membrane and, in addition, better flow-wise or biocompatibleadaptation of the blade to the medium to be conveyed (e.g. blood)becomes possible. In addition, this can mean weight and stabilityadvantages since the lamellae per se require for example a metal framewhich is then coated or sprayed over with a plastic material membrane ora polymer matrix. This is a significant improvement relative to lamellaarrangements in which the entire blade, as a whole, is reshaped with asingle membrane or a single spraying-around since such arrangements,during compression, require higher forces because of the limiteddeformability of the grouped lamellae.

A particularly advantageous development provides that the at least onelamella and also the hub segment of the rotor segment are in one part.This means that these can be produced integrally or from a unified body,preferably a pipe or a flat material (raw material). The thickness ofthe raw material is preferably 5 μm to 500 μm, more preferably 20 μm to200 μm.

A development provides that at least two adjacent rotor segments areconnected to each other non-rotatably in a form-fit. This can be ensuredby corresponding engagement elements (raised portions/depressions). As aresult, the mounting is significantly simplified in addition. Onedevelopment provides that an individual rotor segment has here a singlehub element and also one, two (or even more) lamellae. For example, therotor segment can have an individual lamella, however also a “wingarrangement” is conceivable in which two lamellae (preferably situatedone opposite the other) protrude. Various arrangements are possiblehere, above all according to how much lamella surface area is required.If in particular a lot of lamella surface area is required, a flatmaterial or even a pipe material for example with a large diameter canbe chosen, a diameter change then being able to take place later in theregion of the hub segment for adaptation to the rotor shaft.

A method for the production of a rotor segment or a blade having aplurality of rotor segments provides that structures for hub segmentsand also lamellae are cut out (for instance by means of a laser by wireeroding or etching) from a (for instance tubular or flat) basic body, aconnection web between hub segment and lamellae remaining in order toensure the advantages of the one-part state. Subsequently, the lamellaecan be plastically deformed in their radially protruding normal state bycorresponding shaping tools, as a result of which they correspond to theexpanded (but not yet subjected to fluid pressure) state of thesubsequent blade. Subsequently, possibly a chemical etching treatment ora further laser treatment of the lamellae can be effected in order toensure for example smooth or different surfaces in order to influencethe technical flow properties of the lamella. For example, also theprofile of the lamella can be adapted here to assist the flow.

Hereafter, the rotor segments can subsequently be joined axially to forma rotor shaft. Preferably, these rotor segments, even when a form-fit isprovided in advance by complementary concavities/raised portions, areconnected to each other by means of material joining methods, forexample glueing or welding.

Another development provides that rotor segments with connection websdisposed between the rotor segments can be worked out of a flat materialand are to be disposed on a rotor shaft by folding the flat material outof the surface plane in such a manner that automatically a helix shapeof the blade is produced.

A further development provides that a plurality of lamellae are part ofone lamella body, these being connected to each other merely in theirfoot region. As a result, again easy collapsibility of the lamellae isachieved since they are not connected in their end region protrudingradially from the rotor (in the expanded state) and hence the lamellaecan individually be deformed easily.

The lamella body can thus be introducible into a hub body such that, inthe unloaded state of the outer tips of the lamellae, a helix shape ofthe blade is formed. For example, the hub body is configured as a shellwith spiral longitudinal slots into which the lamella body is introducedso that later the hub body represents the outer circumference of therotor shaft in the case of a finished catheter pump/fluid pump.

A further development provides that the lamella body in the foot regionof the lamellae has weak portions in order to achieve higher tangentialdeflections of the lamellae with the same force application (comparedwith the state in which there are no weak portions). As a result, goodrigidity of the lamella is achieved, on the one hand, relative to thefluid but, on the other hand, sufficient flexibility is ensured duringthe first deformation of the lamella body into the helix shape.

All of the above-mentioned lamella arrangements make it possible toproduce catheter pumps for introduction into human vessels, inparticular for intraventricular use, a rotor with a blade and the pumphaving a conveying direction for conveying body fluid and the bladehereby having a flow pressure side and a flow suction side.

A development provides that, on the flow pressure side, the proximalregion of a distal lamella covers the distal region of anadjacently-situated proximal lamella. As a result, the type of“stepping” of the lamellae is fixed. The advantage is that a stepping ofthis kind is very blood-compatible. The erythrocytes do not collide withthe step in pumping/flow direction; instead, they “fall down the steps”.

In one embodiment it is possible to finish, to coat and/or to extrusioncoat/insert mold the single lamellae in a way that (at least in regions)a steady/continuous curvature of the blade on the flow pressure sideand/or the flow suction side is given.

A further development provides that application of the lamellae in acompressed state is effected essentially by deflecting the lamellae.This is achieve (for example in an embodiment according to FIG. 13d ) ina way that proximally of the rotor a sheath is positioned and the rotoris introduced into the sheath in proximal direction, wherein thelamellae basically one after another (first the most proximal, then theone distally neighboring the most proximal and so on) are bent (i.e. theblades are not bent in total at once, instead the lamellae are bent oneafter another which has the advantage of lower force requirements). Thesheath may have a tube-shape cross-section.

It is also possible to provide a compressible rotor housing etc. betweensheath and rotor, without changing the above principle of bending thelamellae one after another. Remark: in the context of the patentapplication, “bending the lamellae basically one after another” meansthat especially the beginning (the first phase) of bending of thelamellae happens one after another. In the case of multi-blade rotors,eventually several lamellae having the same axial position arecontemporaneously bent.

It may be noted once again that the above-described coating ofindividual lamellae or groups of lamellae can be effected with amembrane (plastic material- or metal foil) or any other coating.

The invention is shown and subsequently described in the following in adrawing with reference to an embodiment.

There are thereby shown:

FIG. 1 schematically in a three-dimensional view, a rotor shaft and alsoa blade,

FIG. 2 schematically, a part of a blade with a plurality of lamellae,

FIG. 3 a rotor shaft in cross-section with a lamella in two positions,

FIG. 4 a rotor shaft in cross-section with two lamellae in respectivelytwo positions,

FIG. 5 a view of a rotor shaft with four lamellae,

FIG. 6 a view of a rotor shaft with two configurations of lamellae,

FIG. 7 a view of a rotor shaft with two configurations of lamellae and

FIG. 8 a schematic representation of a heart catheter pump with a rotorand blades in a ventricle,

FIGS. 9 to 12 show schematic 3-dimensional illustrations of overlappinglamellae.

FIGS. 13a to 13l an embodiment of the blades according to the invention,these blades consisting of lamellae of adjacently-situated rotorsegments,

FIGS. 14a to 14d embodiments of a blade in which a lamella body isinserted into a spiral incision of a shell body, and also

FIGS. 15a and 15b a further embodiment of a blade which is constructedfrom rotor segments.

FIG. 1 shows a rotor shaft 1 having a blade 2 which is composed ofindividual, schematically indicated lamellae 3, 4, 5. The individuallamellae are mounted pivotably respectively by their feet 3 a, 4 a, 5 aon the rotor shaft 1, the feet of the lamellae together extending aroundthe rotor shaft 1 in a spiral.

In this way, a helical structure of a blade is produced, which effectsan axial conveyance of a liquid in the direction of the arrow 6 duringrotation about the rotor shaft 1.

The particular embodiment of the blade according to the inventionemerges in more detail from FIG. 2. In a first position, the lamellae 3,4, 5 are represented there in the deployed, expanded shape of the blade,the adjacent lamellae abutting closely against each other by theirlongitudinal sides and hence forming a surface which is smooth andsealed for the flowing fluid.

In the position which is illustrated in broken lines and designated with7, the individual lamellae are folded a little far onto the rotor shaft1, it being totally important for the deformability of the blade thatthe individual lamellae 3, 4, 5 are moveable relative to each other, inparticular are displaceable in the longitudinal direction. Consequently,folding of the corresponding surface is unnecessary but the individuallamellae can be folded quite far towards the rotor shaft, as isrepresented in the further position 8 of the lamellae.

As a result, the blade can be extensively compressed, i.e. can bereduced with respect to the radius, relative to the rotor shaft 1 or thelongitudinal axis la thereof.

No noteworthy elastic counterforces are thereby produced either so thatthe rotor can be compressed practically without force if this isrequired for example for introduction or removal of a correspondingfluid pump from a naturally occurring body vessel.

In FIG. 2, if pivotability of the individual lamellae in thelongitudinal direction of the rotor shaft 1 in the plane of the rotorshaft axis is indicated, then the invention is not however restrictedhereto. FIG. 3 shows pivotability of a lamella 3 in the azimuthaldirection, as indicated by the arrow 9.

FIG. 4 shows a further variant of such an embodiment, webs 10, 11 beingprovided on the rotor shaft and the lamellae 3, 4 being mountedpivotably on the webs 10, 11 which extend around the rotor shaft 1 in aspiral. The pivoted positions are represented respectively in brokenlines in FIG. 4.

It becomes clear that the pivoting of the lamellae in the positionillustrated respectively in broken lines leads to compression of therotor. For example, compression of the rotor can be caused by arotational operation of the rotor in a direction opposite to theoperating direction. The deployment of the rotor takes placecorrespondingly by rotation in the operating direction.

Basically, the individual lamellae can also be mounted on transversespars of the rotor shaft 1 and extend in the deployed state parallel tothe longitudinal axis of the rotor shaft. It is important that they canbe collapsed correspondingly individually in order to reduce thediameter of the rotor.

In FIG. 5, a plan view on four lamellae 12, 13, 14, 15 is shownschematically, said lamellae having respectively, in cross-section, arectangular and hollow configuration in order to produce greaterlongitudinal rigidity of the individual lamellae. The objective therebyis that, despite the rigidity of the individual lamellae, the blade intotal can be collapsed easily.

FIG. 6 shows two configurations of lamellae, on the left siderespectively lamellae 16, 17 which have an overlapping lip 18, 19 beingillustrated, adjacent lamellae respectively forming a seal on theoverlapping lip 18, 19 of the adjacent lamella, on the one hand, andbeing supported, on the other hand. As a result, rigidity of the bladein total is produced so that the blade withstands an increased fluidcounter-pressure during operation.

On the right side of FIG. 6, three lamellae 20, 21, 22 are illustrated,each of the lamellae having a web 20 a, 21 a, 22 a extending in theradial direction of the rotor shaft 1.

FIG. 7 shows, on left side of the plan view on the rotor shaft 1, threelamellae 23, 24, 25 which have, on one side 26, a convex protuberanceand, on the other side 27, a concave depression in order that adjacentlamellae engage one in the other and thus can be mutually supportedrelative to an azimuthal pivoting position.

Lamellae 28, 29 are illustrated on the right side of FIG. 7, each of thelamellae having, on their longitudinal sides, a concave and a convexprotuberance with a round cross-section. This design has the advantagethat adjacent lamellae are rotatable about their longitudinal axis in amutually restricted manner.

Basically, the individual lamellae can be mounted on the rotor shaft 1either by means of a pivoting articulation or have a bendable orflexible configuration in their foot region such that they are pivotablein any case as a whole relative to the rotor shaft. The individuallamellae can also be glued by their foot ends respectively individuallyon a flexible strip or can be mounted on the latter in a different way,the strip with the lamellae being able as a whole to be mounted on therotor. As a result of the flexibility of the strip, the pivotability ofthe individual lamellae can then be ensured.

In FIG. 8, the use of a fluid pump with a blade according to theinvention is represented schematically, the pump 30 being positioned ina ventricle 31 and, as indicated by the arrows 32, sucks in blood whichis conveyed into a vessel 33, as is shown by the arrows 34. The pump 30is mounted on a catheter 35, through which a shaft 1 illustrated only inthe region of the pump 30 extends centrally and is actuated rotationallyby means of a motor 36. The shaft moves a rotor 37 which has a blade,illustrated merely schematically.

The pump 30 in the expanded state has a diameter which can be possiblyalso be greater, in the extreme case, than the inner diameter of thevessel 33. For this purpose, the impeller is expanded fully. However, itcan also be compressed in order to introduce or remove the pump 30, theindividual lamellae, as illustrated above, being able to be foldedagainst the rotor shaft 1 and, at the same time, the housing of the pump30 being correspondingly collapsed. For this purpose, this housing canfor example consist of a membrane which is deployed by a frame or by thefluid pressure produced in the pump 30.

FIG. 9 shows three flat lamellae which overlap at their longitudinalsides and can have for example a burr-like connection in theiroverlapping region.

FIG. 10 shows lamellae which have edges angled by 90 degrees along theirlongitudinal sides respectively and with which they hook one into theother, whilst a variant, in FIG. 11, is illustrated with an angle ofless than 90 degrees which likewise allows fixing of the lamellaerelative to each other.

FIG. 12 finally represents a variant with a curved edge which serves forthe same purpose of mutual fixing.

FIG. 13a shows a rotor segment 40 which consists of a hub segment 46 andalso a lamella 43 connected thereto in one part. The rotor segment isproduced from a pipe material, the hub segment 46 essentially stillhaving the diameter of the pipe (of concern hereby is also a ring closedin regions) and the lamella being bent therefrom. For this purpose, thelamella is cut out firstly in its original form by means of a laser beamand subsequently plastic deformability on a moulded body is achieved inwhich the deformation state shown in FIG. 13a is produced. Subsequently,the result is also an etching treatment and for other surface treatmentof the lamellae. In order to produce a final blade (see FIG. 13c ), aplurality of rotor segments are then disposed axially relative to eachother.

Also an individual lamella can hereby be covered with a plastic materialor metal foil/membrane or also can be sprayed-around and/or molded inorder to achieve a greater surface.

FIG. 13b shows another view of the rotor segment 40, it can be seen herehow tension relieving slots 54 are shown in the foot region of thelamella 43.

It can be seen that the rotor segment shown in FIG. 13a /13 b has aclosed annular shape in the lower region of the hub segment. Inaddition, it can be seen that the rotor segment connects the hub segmentand also the lamella in one part.

FIG. 13d shows a further embodiment of a rotor segment which is cut froma pipe material and is not yet completely finished, in the case of whichrotor segment the lamellae 43, 43 a are not yet spread out. Here also,tension-relieving slots 54 can however already be seen, in particularalso form-fitting elements 47 in the form of raised portions can beseen, which can engage in corresponding depressions of axially adjacentrotor segments in order hence to fix the position of the lamellae (laterradially spread out).

A rotor with a blade 42 according to the invention is shown in detailagain in FIG. 13d . The preferred conveying direction of the rotor ishereby characterised by the right-side rotational arrow, it consequentlyresults that the flow pressure side 51 and the (opposite side of thelamellae) is the flow suction side 52. Here a plurality of rotorsegments 40 is disposed axially adjacently by their respective hubsegments 46. There is consequently produced also a stepping of theadjacent lamellae 43, 44, 45 which are disposed on a rotor shaft 41.This rotor shown in FIG. 13d can be part of a fluid pump shown in FIG.8, in particular an intraventricular catheter pump. This is a catheterpump for introduction into human vessels, the rotor with a blade beingdisposed in the distal end region of the catheter pump and the pumphaving a conveying direction for conveying body fluid from distal toproximal and the blade having a flow pressure side 51 (see above) and aflow suction side 52.

It can be readily seen in FIG. 13d that, on the flow pressure side 51,the proximal region of the distal lamella 44 covers the distal region ofthe proximal lamella 43. The result consequently is formation of aclosed blade, at least in the radial outer region of the lamellae. Thelamellae are hereby configured “in the shape of an ice hockey stick”.Consequently a very good overlap in the relevant flow region isproduced, in addition good collapsibility. Finally, even with a highfluid counterpressure, only a small flow loss results due to theabove-mentioned orientation of the stepping of the lamellae.

In addition, it is shown in FIG. 13d that application of the lamellae43, 44, 45 in a compressed state is effected essentially by deflectingthe lamellae in the direction of the flow pressure (see arrow 53). Thisarrow is shown once in the distal and once in the proximal region of therotor. The “ice hockey stick-shaped” design of the lamellae offers theadvantage in addition that, when inserting into a lock situatedproximally of the rotor, a low-force and entanglement-free insertion ofthe rotor is produced.

FIG. 13e shows a further embodiment of a rotor according to theinvention in which two blades 42 and 42 a are provided. The rotor shownin FIG. 13e is a combination of a plurality of rotor segments accordingto FIG. 13 c.

FIG. 13f shows a combination of three rotor segments 40 which form partsof a rotor shaft 41, also three hub segments are hereby disposed insuccession, a common blade 42 is produced.

FIG. 13g shows a simple embodiment of a rotor segment 40 with twolamellae protruding radially therefrom. FIGS. 13h shows furtherembodiments of rotors according to the invention. FIGS. 13l and 13jagain show the rotor segment shown in FIG. 13c , here once again thetension-relieving slots 54 and also the form-fitting end serving for theform-fit being shown even better with 47 (raised portion) and also 48(concavity).

FIG. 13k shows a blade 42 on a rotor shaft 41, FIG. 13l shows twophotographs in which, in the left picture, a blade 42 made of aplurality of lamellae is drawn into an insertion lock 55, the rotorshaft 41 can be seen on the right side. In the right-side picture, theblade 42 is completely inserted in the insertion lock 55.

FIG. 14a shows a further embodiment of a rotor in which a hub body 50has two spiral slots (see FIG. 14b ) into which a lamella body 49 (seeFIG. 14c ) is inserted. The view of a flat material from which thelamella body 49 is cut by means of a laser can be seen in FIG. 14d . Forclarification, a possible spraying-around/covering of a lamella is alsoshown once again in FIGS. 14d and/or 15 a (with cross hatching). Thecross hatching can, in another embodiment, be understood that the entirecross-hatched area is made of flat material.

In FIGS. 15a and 15b , a further embodiment of a blade is shown. Alamella basic body 49 is hereby cut from a flat material, connectionstruts being provided between individual rotor segments. In that theindividual rotor segments are tilted out of the surface plane andrecombined with each other, a helical structure is then producedautomatically. This functions for example in such a manner that,according to FIG. 15a , the rotor segment disposed on the left side isrotated out of the plane and placed on the next element from the left(and so on for the other rotor elements) such that the openings of thehub segment overlap each other. If these hub segments are then disposedon a common rotor shaft, a helical arrangement of the lamellae 42, 43,44 is produced automatically. The lamellae may, in a subsequent formingprocess, be rotated in respect of their longitudinal axis in order toachieve overlapping of the lamellae.

1-26. (canceled)
 27. A rotor for a percutaneous blood pump, the rotorcomprising: a rotor hub having a first end and a second end; a rotorshaft extending into the first end of the rotor hub, the rotor shaftconfigured to rotate the rotor hub about an axis; and a compressible andexpandable continuous helical blade mounted to the rotor hub, thecontinuous helical blade having a pitch that increases along thecontinuous helical blade in a direction from the second end of the rotorhub to the first end of the rotor hub.
 28. The rotor of claim 27,wherein the rotor shaft is configured to rotate the rotor hub in eithera first or a second direction about the axis.
 29. The rotor of claim 28,wherein during rotation of the rotor hub in the first direction, thecontinuous helical blade expands under fluid counterpressure.
 30. Therotor of claim 29, wherein during rotation of the rotor hub in the firstdirection, the expanded continuous helical blade conveys fluid in aconveying direction from the second end of the rotor hub to the firstend of the rotor hub.
 31. The rotor of claim 30, wherein the conveyingdirection extends from a distal end of the continuous helical blade to aproximal end of the continuous helical blade.
 32. The rotor of claim 29,wherein during rotation of the rotor hub in the second direction, thecontinuous helical blade compresses onto the rotor hub.
 33. The rotor ofclaim 29, wherein the continuous helical blade extends radially from ablade root coupled to the rotor hub to a radial blade tip.
 34. The rotorof claim 33, wherein the continuous helical blade is radially orientedfrom the blade root to the blade tip in an expanded state.
 35. The rotorof claim 34, wherein the blade root traces a helix about the rotor hub.36. The rotor of claim 35, wherein the blade root traces a helix whichextends 180° about the rotor hub.
 37. The rotor of claim 35, wherein theblade root traces a helix which extends 360° about the rotor hub. 38.The rotor of claim 33, wherein a radial distance between the blade rootand the blade tip decreases at the distal end of the continuous helicalblade.
 39. The rotor of claim 33, wherein a radial distance between theblade root and the blade tip decreases at the proximal end of thecontinuous helical blade.
 40. The rotor of claim 33, wherein thecontinuous helical blade is formed as an arch extending from the rotorhub.
 41. The rotor of claim 35, wherein the blade root extends from thefirst end of the rotor hub to the second end of the rotor hub.
 42. Therotor of claim 27, further comprising at least a second continuoushelical blade disposed about the rotor hub.
 43. The rotor of claim 27,wherein the continuous helical blade comprises a polymer.
 44. The rotorof claim 27, wherein the continuous helical blade comprises a shapememory material.
 45. The rotor of claim 27, wherein the continuoushelical blade is coated with a polymer.
 46. The rotor of claim 27,wherein the rotor hub comprises a plurality of coupled rotor hubsegments.